1. Field of Invention
The present invention relates to the pharmaceutical field, and more particularly to an antihypertensive pharmaceutical composition.
2. Related Art
In recent years, with the continuous improvement of living standards and the changes in the dietary structure of Chinese people, the increase of life stress, and the increase of the elderly population, the incidence of hypertension is gradually increased, and at the same time hypertension causes lesions to heart, brain, kidneys, and other organs, is closely related to sugar and lipid metabolism disorders and diabetes, significantly reduces the quality of life of patients, and even threatens the lives of patients in serious cases. A large number of international authoritative clinical studies on hypertension suggest that increased efforts for depressing the blood pressure, and active and sustained depressing of the blood pressure in the hypertension patients below 130/85 mmHg (optimally below 120/80 mmHg) may effectively mitigate lesions of target organs such as heart, brain, and kidneys caused by hypertension, reduce or delay complications such as stroke, coronary heart disease, angina, myocardial infarction, renal failure, atherosclerosis, and aneurysm, reduce the incidence of the cardiovascular events, the mortality, and the morbidity, improve the life quality of the patients, and prolong the life of the patients. According to the global mortality statistics of various diseases of the World Health Organization (WHO), the cardiovascular disease deaths represented by hypertension accounts for 36% of the total number of deaths; therefore, improving people's awareness on hypertension is of great importance for early-stage prevention and timely treatment.
2008 Consensus of Chinese Experts in Diagnosis and Treatment of Elderly Patients with Hypertension indicates that, treatment through combined administration utilizes multiple different mechanisms for depressing blood pressure, good antihypertensive effect is achieved, adverse reactions are fewer, and thus being more beneficial for protection of target organs. Numerous studies show that, in order to achieve the purpose of positive and intensive blood pressure depression, 70-100% of the patients need to be administrated with two or more antihypertensive drugs in combination. The combined administration can not only significantly improve the antihypertensive effect due to the additive or synergistic effects of the drugs, but also can reduce the side effects of the drugs, and thus the safety and the patient compliance are improved. A lot of literatures suggest that, due to reasonable combination of two antihypertensive drugs, the adverse effects of the two combined ingredients when administrated separately may also be counteracted. Therefore, when a conventional dose of a single medicine cannot achieve the desired standard effect, it is recommended to adopt a combined administration regimen including compound preparations to treat hypertension patients.
Levamlodipine is an optical pure medicine that is firstly chirally resolved in China, an anti hypertensive medicine that is firstly chirally resolved in the world, and a long-term basic dihydropyridine calcium antagonists, and may be prepared through many methods, see references CN00102701.8 and CN03821593.4. Levamlodipine functions through a site (N site) attached to dihydropyridine on a cell and blocks calcium ions from entering the cardiac and vascular smooth muscle cells in a transmembrane manner, so as to relax the smooth muscle, decrease the vascular resistance, and lower the blood pressure. Presently, clinical trial evidences indicate that, a therapeutic dose of levamlodipine has very slight or no influence on cardiac contractility and atrioventricular conduction, and levamlodipine is a medicine with the minimal effect on sympathetic excitation among the calcium antagonists. Levamlodipine may also be used to treat hypertension associated with heart failure, reverse ventricular hypertrophy, improve the relaxation function of the heart during the diastolic stage, protect the renal function with mild diuretic function, and prevent coronary heart disease, myocardial infarction, and stroke, and may further partially reverse abnormal circadian rhythm of blood pressure, and have mild anti-platelet effect, anti-myocardial ischemia effect, anti-arrhythmia effect, insulin sensitivity increasing effect and a certain anti-atherosclerosis effect. However, in a blood pressure depressing process, levamlodipine may easily cause sodium and water retention due to the high dosage, thus resulting in edema, so considerable patients withdraw, and the clinical application of levamlodipine is limited.
Indapamide is a non-thiazide diuretic antihypertensive medicine and a sulfonamide derivative, has a half-life of 17 h, and the metabolites thereof still have antihypertensive effect, so indapamide is a diuretic having a certain calcium antagonism. The antihypertensive mechanism of indapamide is complicated and includes that □ through the influence on the prostate substances, PGI2 (prostaglandin I2) and PGE2 (prostaglandin E2) are increased, and PCF2α (prostaglandin F2α) and TXA2 (thromboxane A2) are decreased, such that the hemorheology is improved, in which PGE2 and PGI2 have the function of dilating the coronary artery and peripheral vessels; □ through reduction of the response of the vascular wall to sodium ion, the calcium channels of the vascular wall cells are inhibited, and the sodium re-absorption of renal distal tubular is slightly inhibited, to relax the smooth muscle, dilate the vessels, and achieve the effects of diuresis and natriuresis, thus achieving the antihypertensive effects. The diuretic may mitigate the edema due to sodium and water retention caused by CCB, but indapamide has the side effect of glucose metabolism interference, so use of indapamide at high dose in long term may cause hypokalemia.